Devices for single sheet feeding of paper



Aug. 12, 1969 E. FORTH 3,460,8

DEVICES FOR SINGLE SHEET FEEDING OF PAPER Filed April 5, 1967 United States Patent US. 'Cl. 271-37 9 Claims ABSTRACT OF THE DISCLOSURE A device for single sheet feeding of paper in particular where employed in paper-folding machines and paperprocessing machinery wherein a retard roll is eccentrically mounted on a shaft spaced from a feed roll and an indexing means is mounted directly on one end of the shaft and in alignment therewith to rotate the retard roll to thereby adjust the distance between the rolls and wherein the eccentricity of the retard roll is such that the incremental differentials when the retard roll and the feed roll are close together are small in comparison to the incremental differentials when the retard roll and the feed roll are far apart.

The invention relates to a single sheet feed control device for use with stacks of sheets of paper and processed, for example, in upsetting folding machines.

It is an aim of the invention to provide a practical and easily operated single sheet feed control device for paper. Advantageously, the operating elements are located on the outside of the side frames of such folding machines. This ensures easy operation and rapid resetting should there be frequent changes in paper thickness. This advantage is of particular importance in the case of light oflice-type folding machines where daily letters with differing numbers of pages have to be handled.

The present invention also makes it possible to cope with various paper thicknesses by simply adjusting a knob relative to a calibrated scale which corersponds to the particular paper thicknesses. This circumvents the laborious manual adjusting procedures occurring in the known single sheet feed control devices. Of special significance in this context is the fact that it has been possible to effect a kind of adjustment in which the scale differences at the start, i.e. corresponding to small thicknesses of paper, are relatively small however, upon increasing pass section, the scale dilferentials increase. This overcomes the difficulties hitherto encountered in setting the pass section for thin sheets of paper.

It is also an aim of the invention to reduce the amount of manual effort required in adjusting the particular paper thickness. This is rendered possible by the fact that the calibrated knob co-operates with a set of ratchets which are held in mating engagement by a spring. This means that when setting up a new paper thickness, there is no locking arrangement to release and subsequently engage.

Further, it is an aim of the invention to provide an accurate and convenient indexing of the retard roll and thereby of the distance between the retard roll and the feed roll by positioning the indexing means directly on the shaft supporting the retard roll.

Accordingly, the invention consists in a single sheet feed control device for sheets of paper, comprising a feed roll, a retard roll eccentrically mounted on a shaft and spaced from the feed roll, and indexing means disposed on the end of the shaft for rotating the retard roll to discrete positions to thereby incrementally vary the distance between the rolls, wherein the change in distance between the roll corresponding to consecutive discrete positions of the retard roll when the rolls are relatively close together is substantially less than the change in distance between the rolls corresponding to consecutive positions of the retard roll when the rolls are relatively far apart.

Preferably, the indexing means includes a rotatable ratchet toothed disc connected to the shaft for rotation therewith and a fixed ratchet toothed disc mating with the rotatable ratchet toothed disc at discrete positions.

In a preferred embodiment of the invention, a calibrated knob is located on the outside of the machine frame, and is connected to an indexing ratchet member spring biased into and disposed on the end of the shaft supporting the retard roll.

Test have established several favourable dimensional relationships which are expedient in particular where the invention is applied to an easily transportable office machine in which frequent readjustments to different paper thicknesses have to be carried out. Series of test have shown for example that an adjustable paper pass slot of between 0.00 mm. and a maximum of 0.8 mm. is adequate for most normal paper qualities.

The pass slot of 0.8 mm. is also adequate for handling multi-page letters, put together for example by hand and introduced into the feed rolls. In the case of multipage letters, the pass slot has to be of suflicient size to ensure that there is no frictional contact between the rotating feed roller and the uppermost sheet. This is the case with the 0.4 mm. eccentric or with a maximum pass slot of 0.8.

It has also been established that with a. 0.4 mm. eccentric face-toothed interlocking discs with teeth yield sufficiently fine increment for papers ranging between 30 and g./m. The pointer knob operates through a maximum arc of The eccentric adjustment is such that with the retard roll at its most eccentric and with the minimum pass slot of 0.00 mm., the scale pointer indicates zero. Any higher scale indication than this produces a downward motion on the part of the eccentric point and thus an enlargement of the pass slot. With the 0.4 mm. eccentric the following pass slots would be obtained from stage to stage:

Stage 1:0.005 mm., stage 2:0.01 mm., stage 3:0.02 mm., stage 4:0.035 mm., stage 5 0.05 mm., stage =0.07 mm., stage 8==0.09 mm., stage 10:0.1 mm. From this relationship, it is clear that the differentials between the first four stages is generally substantially less than differentials between the later stages in order to enable the device to be used for various types of fine paper where slight differentials in paper thicknesses require corresponding differentials in the pass slot.

According to the principle of the invention, the application of the eccentricity may be effected at a different point in the transmission arrangement. Accordingly, the eccentricity of 0.4 mm. for example is provided by the two shaft bearing positions at the side frames, while the retard roll is carried concentrically on the setting shaft.

The invention will now be described with reference to the accompanying drawings which show an embodiment of the invention; wherein:

FIGURE 1 is a cross-section through a device for single sheet feeding of paper;

FIGURE 2 illustrates the same arrangement as FIG- URE 1, with manual introduction of sheets;

FIGURE 3 is a section through the setting control, with the pointer knob;

FIGURE 4 is a front elevation of the device;

FIGURE 4' is a detail of an alternative embodiment of the eccentric adjustment shown in FIGURE 4;

FIGURES 5 and 6 illustrate different settings;

FIGURE 7 illustrates an enlarged eccentric diagram.

The device of FIGURE 1 includes a stacking table 1 which is angulated downwards, upon which table lies a paper stack 2 in an inverted stepped arrangement. Two upstanding pieces 3 serving as guides, to align the stack. The top sheet 4 comes into contact with the feed roll 5, which is of the free-wheel type, then is drawn through a pass slot 6 the size of which can be varied by means of eccentrically adjustable retard rolls 7, and finally conveyed to the folding rolls 8 and 9.

In FIGURE 2, the same arrangement as that shown in FIGURE 1 is illustrated, with the distinction that a multi-sheet set of paper, e.g., a three-page letter 10, is being introduced by hand. To this end, the pass slot 6 has been widened to such an extent that the feed roll 5 cannot exert any traction upon the sheets of paper and these latter are being feed directly up to the folding rolls 8 and 9. By rotating the spindle 11 and the retard roll 7 eccentrically mounted thereon, the pass slot 6 can be enlarged or reduced to accommodate various paper thicknesses. The feed roll 5 is driven by the shaft 12 via the pulley 13. The shaft 12 and the adjusting shaft 11 are mounted in the side frames 14 and 15 of the folding machine. Using the pointer knob 16 which is provided with a rotatable ratchet toothed disc 17 in engagement with the fixed ratchet toothed disc 18, the setting shaft 11 and the eccentric 19 attached to it, with its associated retard roll 7, can be adjusted to correspond to particular paper thicknesses. Instead of mounting an eccentric 19 on shaft 11, it is possible to eccentrically adjust the distance between the retard roll 7 and the feed roll 5 by eccentrically mounting the shaft as shown in FIGURE 4. FIGURE 4 shows a shaft 11 having eccentrically mounted end portions for rotation in the side frames. The axes of rotation of the end portions being displaced by a distance 20' from the axis of rotation of the shaft 11'. The retard roller 7 and the part 19 are coaxially mounted on the shaft 11. Upon rotation of the shaft 11 an eccentric adjustment is achieved as in the embodiment of FIGURE 4. The eccentricity 20 of the retard roll 7 in relation to the setting shaft 11 amounts to 0.4 mm. Rotation of the pointer knob 16 through 180 thus means that the pass slot 6 can be varied from 0 mm. to a maximum of 0.8 mm. and thus adapted to the thickness of the paper in use. Accordingly, in the context of the invention it is clear that the device for single sheet feeding includes the use of such a device on sheets of paper arranged together.

FIGURE 3 illustrates a section through the setting mechanism. The pointer knob 16 is non-rotatably fixed to the extension 21 of the setting shaft 11, by means of the screw 22 and the crosspin 23 for rotation movement with the setting shaft 11. The bush 18 fixed to the side frame section 14, carries fixed ratchet toothed disc 24 which engage cooperating movable ratchet toothed disc 17. A crosspin 23 and an extension 21 are disposed in the groove 25 to thus provide a rotational connection with the setting shaft 11. To change the size of the pass slot 6, the pointer knob is rotated which causes the ratchet toothed disc 17 out of mating cooperation with the ratchet toothed disc 24 to another pointer knob position at which position the compression spring 27 returns the ratchet toothed discs 17 and 24 to mating cooperation.

Tests have indicated that an irreversible eccentric adjustment of the retard roll 7 is achieved using a 0.4 mm. eccentric, if the ratchet toothed discs 17 and 18 are made of synthetic material and the tooth height is 0.8 mm., the compression spring 27 requiring a minimum wire thickness of 2 mm. in order to supply the requisite restoring force.

In FIGURE 5, a position is indicated corresponding to a pass slot 6 suitable for a g./m. paper. The pointer 28 of the knob 16 is set at the corresponding number on the scale 29.

In FIGURE 6, the knob 16 has been set to accord with a paper quality of approximately 200 g./m. The corresponding pass slot 6 between retard roll 7 and feed roller 5 is such as to pass the corresponding sheet 4.

FIGURE 7 provides a diagram showing that the settings of the eccentric pass from the fine divisions 30 and 31 to coarser divisions e.g., 32 and 33. The largest eccentric displacement is indicated by the arrow 34 and can amount to 0 .8 mm.

I claim:

1. A single sheet feed control device for sheets of paper, comprising a feed roll, a retard roll eccentrically mounted on a shaft and spaced from the feed roll, and indexing means disposed on the end of the shaft for rotating the retard roll to discrete positions to thereby incrementally vary the distance between the rolls, wherein the change in distance between the rolls corresponding to consecutive discrete positions of the retard roll when the rolls are relatively close together is substantially less than the change in distance between the rolls corresponding to consecutive positions of the retard roll when the rolls are relatively far apart.

2. A device as claimed in claim 1 wherein the indexing means includes a rotatable ratchet toothed disc connected to the shaft for rotation therewith and a fixed ratchet toothed disc mating with the rotatable ratchet toothed disc at discree ositions.

3. Device as claimed in claim 2 wherein the retard roll has an eccentricity of 0.4 mm.

4. Device as claimed in claim 3, wherein the eccentricity of 0.4 mm. is included in two shaft hearings in the frame, and the retard roll is coaxially mounted on the shaft.

5. A device as claim in claim 2 wherein the device is disposed in a frame and a calibrated knob for rotating the rotatable ratchet is mounted on the outside of the frame.

6. Device as claimed in claim 5 wherein the height of the teeth on the ratchet toothed discs is about 0.8 mm.

7. A device as claimed in claim 5 wherein a spring normally biases the rotatable ratchet toothed disc in mating engagement with the fixed ratchet toothed disc.

8. Device as claimed in claim 7, wherein a scale Surround the calibrated knob.

9. A device as claimed in claim 7 wherein the calibrated knob is connected to the rotatable ratchet-toothed disc by a pin and slot arrangement.

References Cited UNITED STATES PATENTS 2,224,138 12/ 1940 Trydal 271-37 2,670,954 3/ 1954 Bach 27137 3,074,710 l/1963 Olson 271-37 X M. HENSON WOOD, 111., Primary Examiner RICHARD A. SCHACHER, Assistant Examiner 

